JPH07264821A - Brushless three-phase alternator - Google Patents

Abstract

(57) [Abstract] [Purpose] To obtain a brushless self-excited generator composed of a single winding and a single pole number without providing a special exciting circuit or an external exciting current. [Configuration] Three-phase armature winding N on the stator side 2 of the generator 1
_A , N _B , and N _C are provided, and the number of turns of the one-phase winding N _A is larger than that of the other two phases, and the reactor 12 is provided in parallel with the one-phase winding N _A. Also, the field core 5 on the rotor side 3
Is provided with a field winding 7 in which a diode 13 is connected in series.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a self-excited three-phase generator, which does not require an exciting current from the outside via a slip ring or the like, and can be applied to a load without providing a special exciter or voltage regulator. The present invention relates to a brushless three-phase AC generator that can be used.

[0002]

2. Description of the Related Art Known examples of conventional brushless three-phase generators include Japanese Patent Publication No. 24742/1993 and Japanese Patent Publication No. 31379/1990. These components shown in FIG. 5 include a stator 15 and a four-pole three-phase main generator winding 16
And a semiconductor element 17 connected in series with a two-pole single-phase excitation winding 18, and a rotor 20 having a four-pole field core 19 is magnetically coupled to the excitation winding 18. The winding 21 is wound and a rectifying element 22 having a half-wave rectifying action is connected to the field winding 21.

Further, the first known technique is the rotor 20-4.
A field winding 21 in which a rectifying element 22 is connected to the three poles of the pole-shaped field core 19 is wound so as to magnetize S, N, S or N, S, N in the pole order. ing. In the second known technique, the main power generation winding is provided with a light emitting element that emits light when the output voltage of the main power generation winding exceeds a predetermined value, and is connected to one of the field windings of the rotor. The light receiving thyristor is connected in parallel with the rectifying element.

These devices do not require a DC power supply for supplying an exciting current to the exciting winding and a field winding for one pole,
It is characterized in that it is provided with an automatic voltage adjustment that suppresses fluctuations in the output voltage due to load fluctuations, or that the output voltage adjustment during a phase-advanced load is made to function effectively.

[0005]

As in the above-mentioned first known technique, it is necessary to provide a main power generating winding and an exciting winding separately from the main generating winding on the stator side. Providing two kinds of windings in this way complicates the shape and size of the slots of the stator and increases the size. It is not possible to have a simple structure, and this generally leads to a decrease in efficiency. Moreover, although the DC current and a part of the field winding are omitted, not only is the imbalance on the field side rotating at high speed inevitable, but it is also possible to rectify only three poles of the four-pole salient-pole rotor. Since the field winding to which the element is connected is wound, the electromotive force is different in the field pole without the winding, which adversely affects the output waveform of the main power generation winding.

As in the second known technique, a light-receiving element is provided in the main power generation winding and a light-receiving thyristor is provided in the field winding in parallel with the rectifying element to provide an automatic voltage adjusting function. However, the light-receiving thyristor acts due to the voltage increase due to the phase-advance load, and the action of the light-receiving thyristor causes a part of the field winding to be short-circuited in the conductive state. There is a problem in that the power generation action occurs in the state, and it is inevitable that the output waveform is adversely affected as in the above case.

Also, regarding the reliability of the element, since the light receiving thyristor is provided on the field side that rotates at a high speed, that is, on the rotor, the maintenance of this light receiving thyristor requires disassembly of the generator. As long as the light is received, this work is a regular essential work, and it has been a factor that makes maintenance troublesome, as opposed to improving the performance of the generator.

[0008]

In order to solve the above-mentioned problems, the present invention provides a stator core with three-phase armature windings so that the magnetic flux produced by one phase of the armature windings is higher than the other two phases. A stator in which a reactor is connected in parallel to the increased one-phase armature winding and a field conductor concentrically with the stator core and a rectifying element is connected to the field core. To form a brushless three-phase AC generator from the rotor having the same number of magnetic poles as the stator.

In the stator, one of the three-phase armature windings provided on the stator core has more turns than the other two phases, or the stator core is provided. The coil pitch of the three-phase armature winding was changed to increase the magnetic flux produced by the one-phase armature winding.

Further, in the rotor, the field core is formed into salient poles having the same number of poles as the stator, and a field winding in which a rectifying element is connected in series to the salient pole is wound to form an N pole. A half-wave rectification circuit is configured so that S poles are alternately generated, or a field winding in which the field core is formed in a cylindrical shape and a rectifying element is connected in series to the field core is wound and fixed. N with the same number of magnetic poles as the child
A half-wave rectification circuit is formed so that the poles and the S poles are alternately generated, or the field core of the rotor is formed in a cylindrical shape, and the field winding having the same number of magnetic poles as the stator is formed into a three-phase star shape. And a rectifying element was connected between two lines of the three phases to form a half-wave rectifying circuit so that N poles and S poles were alternately generated.

[0011]

In the brushless three-phase AC generator of the present invention, one of the three-phase armature windings provided in the stator core produces more magnetic flux than the other two phases, and more And a stator in which a reactor is connected in parallel to the one-phase armature winding and a field core concentrically with the stator core, and a field conductor in which a rectifying element is connected to the field core. And a rotor adapted to generate the same number of magnetic poles as the child.

At this time, the number of turns of the one-phase armature winding among the three-phase armature windings is greater than that of the other two phases, so that the magnetic flux generated by the one-phase armature winding is increased. The following operation will be described focusing on the case where the magnetic flux is made larger than the other two-phase magnetic flux.

In the brushless three-phase AC generator configured as described above, the rotating shaft of the field core is rotationally driven by the prime mover.
First, when the prime mover is rotated with no load, the residual magnetism of the field core induces a voltage in each of the stator armature windings. Here, a device for assisting this self-excited phenomenon may be provided. Now, at this time, the current flowing in the reactor provided in parallel with one phase of the armature winding is proportional to the induced voltage of the armature winding connected to the reactor, and the exciting current of the reactor is the one-phase armature winding. An alternating magnetic field will be generated in the winding. This alternating magnetic field can be decomposed into a positive-phase and negative-phase rotating magnetic field. Among them, the negative-phase rotating magnetic field interlinks with the field winding of the field core and induces a voltage in the field winding. . A rectified current flows through the field winding through the rectifying element due to the induced voltage, and the DC component thereof forms N, S, N, and S magnetic poles in the field core when there are four poles, for example. Since the magnetic flux of this magnetic pole formed in the field core is rotated by the prime mover, it interlinks with the armature winding and the induced voltage in the armature winding is further increased.

Looking at the one-phase terminal voltage in which the number of turns of the armature winding is large, in addition to the voltage induced in this armature winding,
A voltage drop occurs due to the internal reactance of the winding and the exciting current of the reactor, and this voltage drop compensates for the difference between the induced voltage in the winding of the other phase due to the large number of windings in the armature winding. It has become a thing. In other words, even if the number of turns of one phase is large, the three-phase balance of the output of the armature winding can be sufficiently secured.

Next, let us look at the magnetic fields produced by the armature windings of each phase when a load current flows. The magnetic flux produced by one phase, which has a large number of windings, is larger than the magnetic flux produced by the other two phases by the number of windings, and is the total of the magnetic flux generated by the exciting current of the reactor. Here, if the load current is a lag current, the anti-phase component rotating magnetic field increases, and conversely, if the load current is a lag current, the anti-phase component magnetic field decreases, and for a load current with a power factor of 100%, It is a great advantage of the present invention that the antiphase rotating magnetic field increases as the current value increases. As a result, when the load current changes, the induced voltage in the field winding changes, the rectified current changes, the strength of the field pole changes, and finally the induced voltage in the armature winding changes. It compensates for the fluctuation of the voltage drop due to the change of the power factor of the current and the change of the magnitude of the load current.

Further, in the stator of the brushless three-phase AC generator of the present invention, one of the three-phase armature windings provided in the stator core produces more magnetic flux than the other two phases. In order to achieve this, the explanation of the operation was advanced centering on the case where the number of turns of the one-phase armature winding among the three-phase armature windings provided in the stator core is greater than that of the other two phases. The present invention can be realized by changing the coil pitch of the three-phase armature winding provided on the core to increase the magnetic flux generated by the one-phase armature winding.

By the way, the shape of the field core or the shape of the rotor according to the present invention may be salient poles or cylinders. The cylindrical shape is suitable for high-speed operation with a small number of poles.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present invention will be described with reference to FIG. FIG. 1 shows the principle of the brushless three-phase AC generator of the present invention separately for the stator side 2 and the rotor side 3. First, the stator side 2 is a three-phase four-pole armature winding N _A , N _B , N
_C is provided on the stator core 4, of which the armature winding N
_A is the number of turns (N is greater than the number of turns of the other armature windings N _B and N _C )
+ Some as N _{O). A} reactor 12 is connected in parallel to the armature winding N _A. A load is connected to the output terminals of these three-phase armature windings. On the other hand, rotor side 3
Is three-phase armature winding of the stator side _{2 (N A, N B,} N C)
Is formed on a salient pole type field core 5 having the same number of poles as the above, and a field winding 7 in which a diode 13 as a rectifying element is connected in series is attached to each salient pole 6A to 6D. . The number of turns at this time is such that the field winding is wound such that the magnetic poles formed on the salient poles 6A to 6D by the DC component of the rectified current by the diode 13 have N poles and S poles alternately appearing. is there. That is, it is adapted to the magnetic pole by the armature winding. The rotor 3 has its rotating shaft 8 driven to rotate by a prime mover 9 to generate electric power.

Although the configuration of the present invention has been described in the form of a three-phase four-pole configuration, this does not limit the implementation with other pole numbers. Also, as a rectifying element, simply diode 1
However, there are various types of diodes, and the diode is not limited to this, and a diode that acts as a rectifying element may be used. Further, the magnetic poles 6A to 6 of the salient pole type field core 5 are
As for the shape of D, it is possible to implement an arc shape so that the output voltage waveform approaches a sine wave. The armature winding N _A has a larger number of turns than the other armature windings N _B and N _C by N _O. The output terminal A of the armature winding described above,
B and C are connected to the load.

Further, in the embodiment, all the field windings wound around each salient pole are connected in series, but it is also possible to provide a diode and a field winding for each salient pole as in the known example. Is. Further, the rotor is not limited to the salient pole type, but may be a cylindrical type.

The operation of the above configuration will be described. First, when the rotor side 3 is rotationally driven by the prime mover 9 with no load, the residual magnetism of the field core 5 induces voltages E _A , E _B , and E _C in the armature winding on the stator side 2. In order to help this self-excitation phenomenon, a capacitor 14 is installed at the output terminal of the generator or a permanent magnet 23 is embedded in the rotor core.

Next, for this voltage,
If the induced voltage per unit is e, then each of the voltages E _A ,
E _B and E _C are as follows.

[0023] _{E A = (N + N O} ) e E B = a 2 Ne E C = aNe ( although ^a = ε j2π ^{/ 3)} The reactor 1 connected in parallel to the A-phase armature windings N _A
The current i _L flowing through 2 is proportional to the voltage E _A.
The exciting current of the reactor 12 causes the magnetic flux Φ _A to be generated in the A-phase armature winding N _A. That is, Φ _A = k (N + N _O ) i _L , where k is expressed by a constant, which is an alternating magnetic field.
Can be decomposed into two rotating magnetic fields.

Φ _A COS ωt = (Φ _A / 2) ε ^jωt +
(Φ _A / 2) ε- ^jωt Here, (Φ _A / 2) ε ^jωt is the anti-phase rotating magnetic field that rotates in the opposite direction to the rotating direction of the rotor side 3, so the field winding 7 of the field core 5 Induces a voltage by interlinking with. As a result, a rectified current flows through the field winding 7 through the diode 13, and the DC component thereof forms N, S, N, S magnetic poles in the field core 5. Since this magnetic pole is rotationally driven by the prime mover 9, the induced voltages E _A , E _B , and E _{C of the} armature winding are
Will increase.

[0025] where A phase armature winding N _A terminal voltage V _A of
Considering the above, since the exciting current of the reactor 12 flows in the internal reactance X _A of the A-phase armature winding N _A , the terminal voltage V _A can be expressed as follows.

[0026] _{V A = E A -jX A (} -ji L) = E A -X A i L , i.e. the terminal voltage V _A is the voltage E induced in the armature winding N _A
It is smaller than _A by X _A i _L. Thus each phase terminal voltage V _A, V _B, V _{C is, V A = E A -X A} i L = (N + N O) e-X A i L V B = a 2 Ne V C = aNe next, A Phase The reactor 12 compensates for the difference in induced voltage due to the fact that the number of windings of the armature winding N _A is larger than that of the other phases by N _O, and even if the number of windings of the armature winding is larger than that of the other phases, as a whole. Output voltage is three-phase balanced.

Next, looking at the magnetic flux produced by the armature winding of each phase when the load currents I _A , I _B and I _C flow, the induced voltage E
_The three-phase equilibrium current with _A as the reference is I _A , a ² I _A , a I _{A
Next, Φ A = k (N +} N O) - represented as _{(ji L + I A) =} kNI A -k (N + N 0) ji L + kN O I A Φ B = kNa 2 I A Φ C = kNaI A. Here, the first term of each phase is kNI _A , kNa ²
I _A and kNaI _A, which are three-phase positive-phase rotating magnetic fields. Also it is the value of the term except the first term of [Phi _A of the A-phase [Phi _A 'When _{Φ A' = -k (N +} N O) ji L + kN O I A.

There are various loads, but considering the case where the load current is a delay current, I _A = −jI _A , so Φ _A ′ = −k (N + N _O ) ji _L −kN _O jI _A From the second term of the equation, when the delay current I _A increases, Φ _A '
It is clear that the absolute value of
_Since A'exists only in the A phase and does not exist in the B and C phases, it is an alternating magnetic field, and similarly to the above action, the antiphase rotating magnetic field of the alternating magnetic field increases in proportion to the delay current I _A. . As a result, the induced voltage in the field winding 7 of the field core 5 increases, the rectification current by the diode 13 increases, the field pole becomes stronger, and the induced voltages E _A , E _B in the armature windings increase. It will increase E _C.

From the above, the generator 1 of the present invention is not only brushless, but also compensates for the voltage drop due to the delayed phase of the load current without providing a special voltage regulator or exciting winding. It has an action. The present invention also has a function of compensating for a voltage drop caused by an increase in the output of the generator regardless of the power factor of the load current. Could be provided.

Further, it is possible to change the output voltage by providing a tap on the reactor 12 and switching the tap in order to have a wider range by adjusting the voltage or characteristics. The characteristics can also be changed by controlling the current flowing through the reactor 12 with a triac or the like.

Next, a second embodiment of the present invention will be described with reference to FIG. In this embodiment, the description of the stator side 2 having the armature windings is duplicated and therefore omitted in the drawings and the rotor side 3 is omitted.
Only those are illustrated and their details will be described. FIG. 2 shows a cylindrical field core 10 having four poles as an example of a diode as a rectifying element so that the number of poles is the same as that of the three-phase armature winding on the stator side 2. A field winding 11 having 13 connected in series is wound. At this time, the cylindrical field core 1
The magnetic poles formed at 0 are wound so that N poles and S poles appear alternately. The rotor side 3 is driven to rotate by a prime mover (not shown) to generate electric power, as in the first embodiment. The winding form of the field winding 11 here is
It suffices that the armature winding and the number of poles match.

The operation in the above construction is exactly the same as that of the first embodiment described above, but when the rotor has a cylindrical shape, it is structurally suitable for high speed rotation.

By the way, in the rotor of the second embodiment, as shown in FIG. 3, field windings are wound in three phases and star-connected, and a diode is connected between the two wires (between terminals). It is also possible to connect and configure.

In the above-described embodiment, the stator is one in which the number of windings of one-phase armature winding of the three-phase armature winding provided in the stator core is larger than that of the other two phases. However,
As another example, FIG. 4 shows that the coil pitch of the three-phase armature winding provided on the stator core is changed to increase the magnetic flux generated by the one-phase armature winding. In other words, FIG.
As in (a), the coil pitch of the two-phase windings N _B and N _C of the three-phase armature windings is made smaller than that of the remaining one-phase winding N _A. Similarly, it is possible to increase the magnetic flux generated by the one-phase armature winding N _A. In other words, the induced electromotive force becomes maximum when the coil pitch is the same as the magnetic pole pitch, and when the coil pitch becomes smaller than the magnetic pole pitch, the induced electromotive force becomes proportionally smaller. This can be easily achieved by making the pitch relatively large. Further, as shown in FIG. 4B, the pitches of the windings N _B and N _C are partially changed and the number of windings of the winding N _A is increased to adjust the number of windings and the coil pitch. When used together, the magnetic flux can be adjusted with a wide range.

[0035]

As described above, according to the present invention, the number of magnetic poles of the windings may be the same on the armature side and the field side of the generator, and another exciting winding having a different number of poles is provided as in the conventional case. Of course, by providing a single winding conductor for both the armature and the field, the shape and size of the slot can be made uniform, and simplification can be achieved, thus enabling cost reduction as a total. I was able to improve.

Further, the present invention has a function of compensating for the voltage drop due to the delay phase of the load current, and has the ability to compensate for the voltage drop due to the increase of the output of the generator regardless of the load power factor. It has a voltage adjusting function.
This makes it possible to provide a brushless generator having a voltage adjusting action that does not require all of these sensors and switches, without the need for a special sensor to be provided on the side of the field rotating at high speed as in the conventional case. It was In addition to this, it is not only brushless, but also electrically maintenance free except for mechanical parts.

[Brief description of drawings]

FIG. 1 is a brushless three-phase generator using a salient pole field magnet of the present invention.

FIG. 2 is a rotor of a brushless three-phase generator using the cylindrical field magnet of the present invention.

FIG. 3 is a rotor of a brushless three-phase generator in which a cylindrical field of the present invention is star-connected.

FIG. 4 is a diagram showing a winding state of a stator winding.

FIG. 5 is a configuration diagram of a conventional brushless three-phase generator.

[Explanation of symbols]

 1 Brushless three-phase AC generator 2 Stator side 3 Rotor side 4 Stator core 5 Salient pole type field core 6 Salient pole 7 Field winding 8 Rotating shaft 9 Motor 10 Cylindrical field core 11 Field magnet Winding 12 Reactor 13 Diode 14 Capacitor 15 Stator 16 Main power generation winding 17 Semiconductor element 18 Excitation winding 19 Field core 20 Rotor 21 Field winding 22 Rectifying element 23 Permanent magnet

Claims (6)

[Claims] 1. A stator core is provided with three-phase armature windings, of which one-phase armature windings generate more magnetic flux than the other two phases and are parallel to the increased one-phase armature windings. A stator having a reactor connected thereto and a field core concentrically with the stator core, and a field conductor having a rectifying element connected to the field core to provide the same number of magnetic poles as the stator. A brushless three-phase AC generator characterized by comprising a rotor. 2. The brushless three-phase AC generator according to claim 1, wherein the number of windings of one phase of the three-phase armature windings provided in the stator core is higher than that of the other two phases. A brushless three-phase AC generator characterized in that the magnetic flux generated by the one-phase armature winding is increased. 3. The brushless three-phase AC generator according to claim 1, wherein the one-phase armature winding is formed by changing the coil pitch of the three-phase armature winding provided on the stator core. A brushless three-phase AC generator characterized by increasing the magnetic flux. 4. The brushless three-phase AC generator according to claim 1, wherein the field core is formed into salient poles having the same number of poles as the stator, and the rectifying element is provided on the salient poles. A brushless three-phase AC generator characterized in that a field winding in which is connected in series is wound to form a half-wave rectification circuit so that N poles and S poles are alternately generated. 5. The brushless three-phase AC generator according to claim 1, wherein the field core is formed in a cylindrical shape, and a rectifying element is connected in series to the field core. A magnetic winding is wound and the same number of magnetic poles as the stator, N pole and S pole.
A brushless three-phase AC generator characterized by being configured in a half-wave rectifier circuit so that poles alternate. 6. The brushless three-phase AC generator according to any one of claims 1 to 3, wherein the field core of the rotor is formed in a cylindrical shape and has the same number of magnetic poles as the stator. The winding is wound in a three-phase star shape, a rectifying element is connected between two lines of the three phases, and a half-wave rectifying circuit is configured so that N poles and S poles are alternately generated. Brushless three-phase AC generator.